The present invention relates to a sensor, in particular a temperature sensor, having a pre-assemblable transmitter insert which is coated by extrusion by an electrically insulating plastic, the insert having a transmitter element intended for the detection of a measurement value, electrical terminals, and electrical connecting elements extending from the transmitter element to the terminals. The invention furthermore relates to an injection molding apparatus having an injection mold and a core which can be moved into the injection mold.
In a known sensor of the above type, the transmitter element is first of all soldered to the connecting lines and then inserted into the injection mold and coated by extrusion with plastic. The regions of the connecting lines which are not to be covered by plastic are, as a rule, held free of the core of the injection molding apparatus and, after the coating of the transmitter insert, they form the terminals of the sensor on which the plug of a connecting line is placed.
The known sensor has the disadvantage that it is expensive to constitute and manufacture. For instance, it is necessary to dimension the connecting lines with a high strength, since otherwise, upon being coated with plastic, the transmitter element can very easily shift to the side from its intended position in the injection mold.
One could think of fastening the transmitter element so as to fix it in its intended position on a holding part which, upon the coating with plastic, rests against the wall of an injection mold. In this way, however, the production of the sensor becomes very expensive. Such an attachment of the holding part, particularly upon series production of the sensor, is very cost-intensive and leads to sensors having a non-homogeneous surface. In order to prevent tilting of the transmitter insert, the holding part, furthermore, must be of very large dimensions.